Christof Koch

Christof Koch is Professor of Biology and of Engineering at the California Institute of Technology and Chief Scientific Officer of the Allen Institute for Brain Science in Seattle. He is the author of The Quest for Consciousness and other books.

Titles by This Author

What links conscious experience of pain, joy, color, and smell to bioelectrical activity in the brain? How can anything physical give rise to nonphysical, subjective, conscious states? Christof Koch has devoted much of his career to bridging the seemingly unbridgeable gap between the physics of the brain and phenomenal experience. This engaging book—part scientific overview, part memoir, part futurist speculation—describes Koch's search for an empirical explanation for consciousness. Koch recounts not only the birth of the modern science of consciousness but also the subterranean motivation for his quest—his instinctual (if "romantic") belief that life is meaningful.

Koch describes his own groundbreaking work with Francis Crick in the 1990s and 2000s and the gradual emergence of consciousness (once considered a "fringy" subject) as a legitimate topic for scientific investigation. Present at this paradigm shift were Koch and a handful of colleagues, including Ned Block, David Chalmers, Stanislas Dehaene, Giulio Tononi, Wolf Singer, and others. Aiding and abetting it were new techniques to listen in on the activity of individual nerve cells, clinical studies, and brain-imaging technologies that allowed safe and noninvasive study of the human brain in action.

Koch gives us stories from the front lines of modern research into the neurobiology of consciousness as well as his own reflections on a variety of topics, including the distinction between attention and awareness, the unconscious, how neurons respond to Homer Simpson, the physics and biology of free will, dogs, Der Ring des Nibelungen, sentient machines, the loss of his belief in a personal God, and sadness. All of them are signposts in the pursuit of his life’s work—to uncover the roots of consciousness.

What links conscious experience of pain, joy, color, and smell to bioelectrical activity in the brain? How can anything physical give rise to nonphysical, subjective, conscious states? Christof Koch has devoted much of his career to bridging the seemingly unbridgeable gap between the physics of the brain and phenomenal experience. In this BIT, Koch argues that consciousness is a fundamental property of networked entities, and rhapsodizes about integrated information theory—how it explains many puzzling facts about consciousness and provides a blueprint for building sentient machines.

Titles by This Editor

Large-Scale Neuronal Theories of the Brain brings together thirteen original contributions by some of the top scientists working in neuroscience today. It presents models and theories that will most likely shape and influence the way we think about the brain, the mind, and interactions between the two in the years to come. Chapters consider global theories of the brain from the bottom up—providing theories that are based on real nerve cells, their firing properties, and their anatomical connections. This contrasts with attempts that have been made by psychologists and by theorists in the artificial intelligence community to understand the brain strictly from a psychological or computational point of view.

The authors encompass a broad background, from biophysics and electrophysiology to psychophysics, neurology, and computational vision. However, all the chapters focus on a common issue: the role of the primate (including human) cerebral cortex in memory, visual perception, focal attention, and awareness.

The neurobiology and psychology of attention have much to learn from each other. Neurobiologists recognize that responses in sensory cortex depend on the behavioral relevance of a stimulus, but have few ways to study how perception changes as a result. Psychologists have the conceptual and methodological tools to do just that, but are confounded by the multiple interpretations and theoretical ambiguities. This book attempts to bridge the two fields and to derive a comprehensive theory of attention from both neurobiological and psychological data. It highlights situations where attention can be seen to alter both neural activity and psychophysical performance/phenomenal experience. This "bicultural" approach contributes not only to attention research but to the larger goal of linking neural activity to conscious experience.

The book focuses mainly on the effects of visual attention on the ventral and dorsal streams of visual cortex in humans and monkeys and the associated changes in visual performance. Several larger findings emerge: attention may involve more than one neural system; attention modulates all stages of cortical visual processing; the effect of attention is constrained by the intrinsic connectivity of cortex and the resulting contextual interactions; and the notion of a "saliency map" remains central to thinking about visual attention. The book also considers several approaches to evaluating the same variable through different methods, such as behavioral measurements, functional imaging, and single-unit recording.

Much research focuses on the question of how information is processed in nervous systems, from the level of individual ionic channels to large-scale neuronal networks, and from "simple" animals such as sea slugs and flies to cats and primates. New interdisciplinary methodologies combine a bottom-up experimental methodology with the more top-down-driven computational and modeling approach. This book serves as a handbook of computational methods and techniques for modeling the functional properties of single and groups of nerve cells.

The contributors highlight several key trends: (1) the tightening link between analytical/numerical models and the associated experimental data, (2) the broadening of modeling methods, at both the subcellular level and the level of large neuronal networks that incorporate real biophysical properties of neurons as well as the statistical properties of spike trains, and (3) the organization of the data gained by physical emulation of the nervous system components through the use of very large scale circuit integration (VLSI) technology.

The field of neuroscience has grown dramatically since the first edition of this book was published nine years ago. Half of the chapters of the second edition are completely new; the remaining ones have all been thoroughly revised. Many chapters provide an opportunity for interactive tutorials and simulation programs. They can be accessed via Christof Koch's Website.